Unitary rigid wire connectors and method of making wire connections



y 1, 1965 w. s. PAWL 3,183,472

UNITARY RIGID WIRE CONNECTORS AND METHOD OF MAKING WIRE CONNECTIONSFiled 001;. 2, 1965 4 Sheets-Sheet l m \m\\\\ v 2 IA/I E/VTOR Mafia KWMay 11, 1965 w, s, P w 3,183,472

UNITARY RIGID WIRE CONNECTORS AND METHOD OF MAKING WIRE CONNECTIONSFiled OCT.- 2, 1963 4 Sheets-Sheet 2 RANGE OF WIRE SIZES LARGEST WIREINSULATION LARGEST WIRE 8| SMALLEST WIRE INSULATION SMALLEST WIRE RANGEOF WIRE INSULATION FIG. IO H6 5 4 NWENTOR May 11, 1965 w. s. PAWL3,183,472

UNITARY RIGID WIRE CONNECTORS AND METHOD OF MAKING WIRE CONNECTIONSFiled Oct. 2, 1963 4 Sheets-Sheet 3 74 FIG. 6 6 e4 54 //VVE/YTUR FIG. llim May 11, 1965 w. s. PAWL 7 UNITARY RIGID WIRE CONNECTORS AND METHOD OFMAKING WIRE CONNECTIONS Filed Oct. 2, 1963 4 Sheets-Sheet 4 UnitedStates Patent 3,183,472 UNITARY RIGID WIRE CONNECTORS AND METHOD OFMAKING WIRE CONNECTIONS Walter S. Paw], 2844 Powder Mill Road, Adelphi,Md. Filed Oct. 2, 1963, Ser. No. 313,282 6 Claims. (Cl. 339-97) Thisinvention relates to improvements in simple wire connector units of thetype illustrated in my joint application with Stephen N. Buchanan, Ser.No. 131,958, filed August 8, 1961, for Rigid Unitary Wire Connectors.

The object of this invention is to make a simple onepiece conductingconnector element having means for receiving a plurality of wires whilebreaking through their insulations to provide high pressure contactsbetween the element and each wire.

A further object is to provide an insulator block around this connectorelement of simple form having a recess for the exposed ends of thewires.

A further object is to provide a closure cap of insulating material toclose said recess and hold said wires in said connector element.

A further object is to provide an inserting tool head inside said capfor pressing said wires into said element, one at a time and to holdsaid wires in said element.

A further object is to provide a waterproof seal between said block andsaid closure cap.

Other and more specific objects will become apparent in the followingdetailed description of some forms of connectors made in accordance withthe present invention as illustrated in the accompanying drawings,wherein:

FIG. 1 is an enlarged vertical sectional view of a simple rectangularblock form of connector unit with a cap shown in exploded position, thesection being taken on the line 11 shown in FIG. 2,

FIG. 2 is a vertical sectional view of the block taken on the line 22 ofFIG. 1, with the cap closing the top of the block,

FIG. 3 is a plan view of the block without the cap,

FIG. 4 is an enlarged sectional view of a cylindrical block form ofconnector unit with a closure cap in exploded position, the sectionbeing taken on the line 4l4 of FIG. 5,

FIG. 5 is a vertical sectional view taken on the line 55 of FIG. 4,

FIG. 6 is an enlarged sectional view of still another block form ofconnector unit with a cylindrical closure cap for completely sealing theconnector unit, with a twist lock means for locking it in place,

FIG. 7 is a sectional view taken on the line T -"'7 of FIG. 6,

FIG. 8 is an enlarged side view of a wire inserting tool,

FIG. 9 is a plan view of this tool,

FIG. 10 shows the comparative sizes of wires and their insulationswithin a range of sizes for which the connector is made,

FIG. 11 is a sectional detail view taken on the line li -11 of FIG. 8,and

FIGS. 12 and 13 illustrate a simple cap type connector with twist lockmeans for easy assembly of the cap over the ends of the connected wires.

The simple connector element 12 may be identical for all the block formsas shown. The element is primarily circular, having segments cut oil onopposite sides 14 and a vertical radially extending slot 16 betweenthese sides, having smooth parallel walls flaring out at the peripheryto pointed ridges 18 spaced approximately a distance equal to thediameter of the insulation or" the smallest size wire in the range ofsizes for which the connector is made, the parallel portions of thewalls being spaced not more than the smallest size wire. The comparativesizes of wires and their insulations within the range of sizes that maybe used in this connector are indicated in FIG. 10. This range may beselected as #12 to #16, #18 to #22, etc., as may be desired, and forwhich the slot may be suitably designed.

The block form Zil, FIGS. 1 and 2, may be a molded plastic insulatormaterial of suitable electrical characteristics, and has a largerectangular recess 22 in its upper portion, in one side of which theconnector element 12 is mounted and extends downwardly into a smallerrecess 24 in the lower portion, with a force lit. The bottom of thisrecess 2 5 is vented by a small bore 26, to facilitate assembly of theelement 12 in this block.

The block 26 has -a guide slot 28 coaxial with the slot 16, and open atthe top of the block to receive and guide the insulated wire over theslot 16, and to prevent bending strain on the inserted wires at thecontact areas when the leads are accidentally pulled to one side or theother of the slot.

For purposes of illustration, three different sizes of wires 3%, 31 and32 are shown in cross section in the slot 16 of the connector element inFIG. 1, 350 being the smallest size and 32 the largest, for which theconnector is designed. The respective terminal ends 33, 34 and 35, ofthese wires extend into the large recess 22, and may be sealed oil by aclosure cap 36 to prevent accidental shorts with external connections inproximity to the connector block.

The closure cap may have a plug portion 33 fitting snugly in the top ofthe recess 22 and forming a tool head portion ill, which may be used toinstall the wires as well as hold them against accidental looseningafter they are installed.

A tool such as shown in FIGS. 8 and 9 may be used to install the wiresin any of these connector units. The tool has a pair of handles 42 and44, pivoted at one end and normally biased to spreading position by aspring 46. The other ends of the handles are provided with a fiatbearing head 48 on the lower handle 44 to place under the connectorblock, and an inserter head 50 on the upper handle 42 to place over theWire in the open end of the guide slot 23, the thicker portions 52 ofthe inserter head being positioned to straddle the connector element andthe thin intermediate portion 54 being held directly over the slot 16.By firmly squeezing the handles of the tool, the Wire is pushed inthrough the flared end of slot 16, where the pointed ridges break intothe insulation on the wire and the flared slot wall-s push it away fromthe contacts as the bare wire enters the paral lel wall portion of theslot 16, and its circular periphery is somewhat flattened by theconvergent Walls of the slot toward the bottom of the flared endthereof. The separated portions of the insulation around these contactshug the adjacent slot wall portions and seal the contacts againstmoisture and oxidation. The smooth slot walls prevent scoring of thewire, merely squeezing it, so that it is not weakened but merelydeformed in cross section sassy/2 by a slight flattening to provide ahigh pressure contact area on opposite sides of the wire with the smoothslot walls.

The slot walls being rigidly held parallel, and being smooth, thedeformation pressure exerted by the walls against the opposite sides ofthe wire is not relieved but is substantially retained even after thewire is moved to the bottom of the slot. This high contact pressureeliminates any possibility of introducing undesirable resistance in theconnector circuit even at high loads.

The highest pull-out strength is also maintained in this type ofconnector, because the cross-sectional area, while it is deformed byflattening at the contacts, is not reduced; nor is the wire weakened bybrittleness due to vibration or excessive heating as in solderedconnections, or where no guide slots are used to dampen vibrations atthe contacts in vibrational environments.

In slot type connectors of the prior art, the contact pressure wasobtained either by wedging in a rigid tapered slot or resilient prongedslot, neither slot being adapted to receive more than one wire. Someslots with substantially parallel side walls have been used, but noattempt has ever been made to compress the wire into these slots, nor toprovide smooth walls for these slots to prevent scoring of the wire,which relieves any deformation compression to which the wire might besubjected before entering such a slot. The present connector element isunique in that it retains a high contact pressure on a plurality ofwires of any size within a predetermined size range and does not weakenthem by scoring or cutting of any kind, while at the same time itprevents weakening due to vibration.

By using a water tight cap, with a resilient sealing plug 56 over thewire in the upper part of the guide groove 28, the present connector ismade highly resistant to extreme vibration and shocks as well as watertight.

A circular block form 6% for the connector element 12 is shown in FIGS.4 and 5, wherein the same arrangement of large and small recesses 62 and64 is used for the wire terminal ends 33, 34 and 35 and the lower end ofthe connector element 12, respectively. The closure cap 66 is similar tocap 36 but is curved to conform with circular periphery of the block 60.A complete seal of the block is attained in the same manner by using aresilient sealing plug 56 to fill the upper part of the guide groove 28over the wire leads stacked in the lower part of the groove 28, when thecap 66 is plugged into the recess 62 tightly. The closure caps arepreferably molded of a somewhat resilient insulator plastic material.

A modified form of the circular block form is shown in FIGS. 6 and 7,wherein the block 67 has segments cut off at opposite sides leaving thinside walls 68 and 7d, the large recess 72 being open at the back as wellas at the top. A cylindrical closure cap 74 is used, having segmentalportions '76 at its open end to slide over the straight sides 68 and 70of the block when installing the cap over the block, and when the cap ispushed against the back end of the block, the segmental portions 76clear the front face of the block so that by turning the cap, it may belocked over the block to completely seal it and at the same time towedge the inner edge of one of the portions 76 over the upper wire 33 tohold all the wires against any accidental loosening by continuousvibration or otherwise. This turning may be facilitated by providingraised portions '78 and 80 on the face of the block and on the back ofthe cap respectively. Either of these raised portions may be formed toprovide an inserting tool 82, as shown in FIG. 7, for pushing the wirethrough the entrance to the slot in the connector.

This same type of tool head 32 is shown as Sti at the end of the upperhandle in the inserting tool of FIGS. 8 and 9, and in cross section inFIG. 11. Obviously, the tool could be made in many other simple forms,as e.g. both handles 42 and 44 could be made of one continuous curvedpiece of spring material instead of having a hinge and the biasingspring 46.

In FIG. 10 the inner circle and the intermediate circle show thecomparative range of sizes of wire in cross section that may be readilyused in the size of slot illustrated, and range of sizes of theinsulation cross section area may be between that of the intermediatecircle for the smallest wire and the outer circle for the largest wirethat it may be feasible to use in this connector slot.

A suitable material for this connector has been found to be a Phosphorbronze of superior hardness and good conductivity and strength. However,any other materials having good electrical conductivity, requiredstrength to maintain rigidity under the operative stresses and othersuitable characteristics, may be used. The same is true of the block andcap materials, which may be selected from a large number of insulatingmaterials having the proper electrical and mechanical characters forbest results.

Another more simple modification of this connector is shown in FIGS. 12and 13. In this case the connector element 90 does not have anyinsulating support block, but is simply insulated after the wires areinserted, by a cap 84 of insulating material, which has an insertingtool head 86 on the outside, and inner segmental locking flanges 88. Thecap thus serves as a tool for inserting the wires in the connectorelement, and then as an insulating cover for the element. These flangesmay be provided with bumps 92 near their ends as shown, so that the capmay be locked by turning in either direction until one of these bumpsreaches the slot and catches over the side wall of the slot entrance 94.The ends of the wires 33, 34 and 35 will tend to push the cap olf andhold it in locked position, but by pressure on the cap it may be turnedto release position and removed. A skirt 96 of suitable length beyondthe flanges 88 may be provided to protect the connector element fromcoming into accidental contact with adjacent conductive materials toproduce a short.

It has been found that a substantially sharp ridge 98 at each side ofthe entrance to flared portion of the slot 1&0 of the connector element90, where the flaring side walls of the slot meet the periphery of theelement 90, is suflicient to start the break into the insulation, afterwhich the break is completed depthwise of the insulation by thesqueezing effect between the wire and the slot wall surfaces, as thewire is forced through the flared portion of the slot, and the linecontact first made between these convex surfaces completes the breakthrough the insulation, which is then squeezed away from the contactsurfaces as they are enlarged from the initial line contacts to flatareas under compression between the parallel sides of the slot. Ridges98 should be spaced to receive the largest size wire in the range forwhich the slot is designed, so that the initial line contacts betweenthe wire and flared portions of the slot sides will fall inside theridges 98 and the wire will not be scored by these ridges. At the sametime this spacing of the ridges should close enough that the ridges maybreak into .the outer edges of the insulation of the smallest size wirein the range for which the slot is designed, as the insulation issqueezed outwardly over these ridges when the wire is pushed into theflared entrance between them.

While only a single slot connection element is illustrated, it is to beunderstood that more than one slot may be used in the same element, thetotal length of their parallel sided portions providing the capacity forthe number of wires desired to be joined together. On the other hand,for terminals requiring only a single wire connection, only a shortsingle slot is required.

The connector slots illustrated are all of the type that open at anouter edge of the connector element. This makes it diflicult to maintainrigidity at the outer end of a long slot without making the connectorelement unduly wide. By cutting a small opening in the connector elementlarge enough to freely pass an insulated wire through it, and extendingthe slot or slots from the inner edge of this opening, the outer ends ofsides of these slots are more rigidly supported against spreading by thearch of the material around the opening. Thus, much less overall widthof the connector element is required. This may be an importantspace-saving feature in multi connector or terminal block structures orother places where screw type terminals are too bulky.

The present connector elements are not only space savers but are alsocheaper to make because of their simplicity, and save installation timebecause no stripping or other preparation of the wires is required. Theyare simply pushed into the slot with a single stroke and the connectionis made, the insulation being automatically pierced and removed from thepoints of contact with the sides of the slot, which flatten the wire atthese points, and the joints are sealed by the remaining insulationaround them.

Many obvious modifications in the form and details of structure of theconnector elements, blocks and cover caps may be made without departingfrom the spirit and scope of the present invention, as defined in theappended claims.

What is claimed is:

1. A rigid unitary connector element of hard conductive material adaptedto connect at least one wire thereto and having at least one slot withsmooth flat parallel sides spaced less than the diameter of wire sizeswhich it is adapted to receive and hold in compression, between itsparallel sides, said sides being flared at one end of the slot toreceive and smoothly compress the wires as they are forced into theslot,

each slot having a flared entrance formed to receive and flatten thewire as it passes therethrough into said slot and to rupture and removeany insulation on the Wire at the flattened pressure contacts with saidparallel sides,

said element being shaped generally like a round disc with a single slotextending diametrically from its edge and with segments cut :oif onopposite sides of the slot parallel thereto,

said slot being long enough to receive at least two wires to provide anelectrical connection between them.

2. A rigid unitary connector element as defined in claim 1, and a hollowinsulating block having a pocket in the bottom at one side of saidhollow in which said element is frictionally mounted, the slot entrancebeing at the top and below the top of the block, the adjacent side ofthe block having a guide slot extending from the top of the block to thebottom of the slot in the connector clement adapted to form a guide forthe wire leads of any inserted wires extending outwardly of said blockand having their ends in said hollow.

3. A rigid unitary connector element of hard conductive material adaptedto connect at least one wire thereto and having a slot with smooth flatparallel sides spaced less than the diameter of wire sizes which it isadapted to receive and hold in compression between its parallel sides,

said sides being smoothly flared at one end of the slot to a gap widerthan the largest of said wire sizes to receive and smoothly compress thewires as they are pushed into the slot,

said connector element being shaped generally like a round disc withsaid slot extending diametrically from its edge and with segments cutoff on opposite sides of said slot and parallel thereto,

said slot being long enough to receive at least two wires to provide anelectrical connection between them,

a hollow insulating block open at the top and having a pocket in thebottom at one side of said hollow in which said element is frictionallymounted,

the slot entrance being at the top and below the top of the block,

the adjoining side of the block having a guide slot extending from thetop of the block to the bottom of the slot in the connector elementadapted to form a guide for the wire leads of any inserted wiresextending through said guide slot outwardly of said block, said hollowbeing large enough to accommodate the inner ends of said wires, and

a cover cap having a plug portion frictionally fitting into the top ofsaid hollow block and a resilient plug for sealing the guide slot abovethe wires mounted therein, whereby the connector block may be completelysealed against moisture and oxidation as well as arcing over from theconnector element and exposed ends of the wires in the hollow of saidblock to adjacent conducting materials, especially at high altitudeswhere flash over would occur through any open cracks in the guide slotseal because of the reduced dielectric strength in the atmosphere whichhas little or no air.

4. A rigid unitary connector element of hard conductive material adaptedto connect at least one wire thereto and having a slot with smooth flatparallel sides spaced less than the diameter of Wire sizes which it isadapted to receive and hold in compression between its parallel sides,

said sides being smoothly flared at one end of the slot to a gap widerthan the largest of said wire sizes to receive and smoothly compress thewires as they are pushed into the slot,

said connector element being shaped generally like a round disc withsaid slot extending diametrically from its edge and with segments cutoff on opposite sides of said slot and parallel thereto,

said slot being long enough to receive at least two wires to provide anelectrical connection between them,

a hollow insulating block open at the top and back and having a pocketin the bottom at the front of the hollow in which pocket said element isfrictionally mounted,

the slot entrance being at the top and below the top of the block,

The adjoining side of the block having a guide slot extending from thetop of the block to the bottom of the slot in the connector elementadapted to form a guide for the wire leads of any inserted wiresextending through said guide slot outwardly of said block,

said hollow being large enough to accommodate the inner ends of saidwires,

said block having thin vertical walls extending back from the straightedges of said connector element, the top and bottom of the blockconforming to the otherwise circular shape of the connector element, theback of the hollow portion of the block being open as Well as the top,and

a cylindrical cover cap of insulating material adapted to be mountedover the entire block from the back and having inner segmental flangesat its outer end corresponding to the spaces in the cap on the oppositeparallel sides of the block, for turning over the front of the block tolock the cap thereon.

5. A rigid unitary connector element of hard conductive material adaptedto connect at least one wire thereto and having a slot with smooth flatparallel sides spaced less than the diameter of wire sizes which it isadapted to receive and hold in compression between its parallel sides,

said sides being smoothly flared at one end of the slot to a gap Widerthan the largest of said wire sizes to receive and smoothly compress thewires as they are pushed into the slot,

said connector element being shaped generally like a round disc withsaid slot extending diametrically from its edge and with segments cutoff on opposite sides of said slot and parallel thereto,

said slot being long enough to receive at least two wires to provide anelectrical connection between them, and

ii a cylindrical insulating cap having inner segmental References Citedby the Examiner flanges corresponding to the segmental cut out por-UNITED STATES PATENTS trons of said connector element, for shpplng overthe a back of said element and turning it to lock said 21333266 11/4333995 flanges over the front of the circular portions of 5 2,501,1373/50 oorFgllsen 339 95 said element. 3,012,219 12/61 Levin et a1. 33998A cc1 1nnect0r ellement and cap asddefined in cliaimbS, FOREIGN PATENTSsal cap aving a s irt portion exten ing ontwar y e- 615 737 1/49 GreatBritain t yond said flanges to protect the front of sald connector659316 10/51 Great Britain element against accidental contact withoutside conduct- 10 ing materials. JOSEPH D. SEERS, Primary Examiner.

1. A RIGID UNITARY CONNECTOR ELEMENT OF HARD CONDUCTIVE MATERIAL ADAPTEDTO CONNECT AT LEAST ONE WIRE THERETO AND HAVING AT LEAST ONE SLOT WITHSMOOTH FLAT PARALLEL SIDES SPACED LESS THAN THE DIAMETER OF WIRE SIZESWHICH IT IS ADPATED TO RECEIVE AND HOLD IN COMPRESSION, BETWEEN ITSPARALLEL SIDES, SAID SIDES BEING FLARED AT ONE END OF THE SLOT TORECEIVE AND SMOOTHLY COMPRESS THE WIRES AS THEY ARE FORCED INTO THESLOT, EACH SLOT HAVING A FLARED ENTRANCE FORMED TO RECEIVE AND FLATTENTHE WIRE AS IT PASSES THERETHROUGH INTO SAID SLOT AND TO RUPTURE ANDREMOVE ANY INSULATION ON THE WIRE AT THE FLATTENED PRESSURE CONTACTSWITH SAID PARALLEL SIDES, SAID ELEMENT BEING SHAPED GENERALLY LIKE AROUND DISC WITH A SINGLE SLOT EXTENDING DIAMETRICALLY FROM ITS EDGE ANDWITH SEGMENTS CUT OFF ON OPPOSITE SIDES OF THE SLOT PARALLEL THERETO,SAID SLOT BEING LONG ENOUGH TO RECEIVE AT LEAST TWO WIRES TO PROVIDE ANELECTRICAL CONNECTION BETWEEN THEM.